1. Field of the Invention
The present invention relates to 3,4-disubstituted phenols, methods for their preparation and, to their use as immunomodulating agents. More specifically, the present invention relates to 3,4-disubstituted phenols having interleukin 1 (hereinafter IL-1) mimetic activity, which can be used as a stimulant of the immune functions.
2. Reported Developments
IL-1 is a 17kD polypeptide hormone which induces a wide range of biological effects by binding IL-1 to a specific receptor protein on responsive cells. Some of the activities of IL-1 include: induction of IL-2 secretion from T cells, induction of fibroblasts to secrete PGE, stimulation of osteoclasts to resorb bone, triggering the appearance of CSF receptors on stem cell progenitors, increasing synthesis of CSF's, activation of T and B cells, induction of cartilage destruction in joints, elevation of collagenase levels in synovial fluid and action as an endogenous pyrogen.
Because of the multiple activities of IL-1, a variety of uses for compounds influencing these responses have been envisioned. An IL-1 agonist or mimetic would have therapeutic applications as an immunostimulant, an anticancer agent or in inducing haemopoesis.
IL-1 has been produced in the prior art by inducing secretion thereof by normal macrophages/monocytes of peripheral blood by means of application of an inducing agent of bacterial origin. IL-1 has also been produced by culturing a human leukemic cell line of haematopoietic origin by means of application of phorbols as inducing agents. Another approach to provide for IL-1 activity is disclosed in U.S. Pat. No. 4,762,914 which teaches the production of truncated protein of IL-1 made by a genetic engineering procedure. The so obtained biologically active human IL-1 protein is said to be useful to induce the production of IL-2 by activated T-cells. Still another approach to provide IL-1 activity is disclosed in U.S. Pat. No. 4,774,320 which concerns the preparation and use of the following peptide that mimics human IL-1 activity:
Val-Gln-Gly-Glu-Glu-Ser-Asn-Asp-Lys-X
where
X cysteine (Cys), OH, NH.sub.2, benzyl ester or an alkyl ester group having a number of carbon atoms from 1 to 7.
IL-2, also known as T cell growth factor, has been found to influence cell-mediated immune responses in mammals, such as: enhancement of thymocyte mitogenesis; production of cytotoxic T lymphocytes; promotion of proliferation of antigert specific killer T cell lines; and promotion of anti-erythrocyte placque forming cell responses.
Disruptions of the immunodefense system can be ascribed to the insufficient presence of IL-2 in the mammalian body, as a result of the lack of cells that produce IL-2, inadequate IL-2 production, or insufficient formation of IL-2 receptors (U.S. Pat. No. 4,752,573). In light of these findings by the prior art, IL-2 appears to be useful in promoting humoral and cellular immune responses and in restoring an immune deficient state to a normal immune state. Accordingly, IL-2 is indicated for medical immunotherapy against immunological disorders, including neoplastic diseases, bacterial or viral infections, immune deficient disorders and autoimmune diseases.
IL-2 has been produced in the prior art by stimulating mouse, rat or human lymphocytes with a mitogen (Gillis, S. et al., Nature, 268, 154-156, (1977), Farrat, J. et al., J. Immunol., 121, 1353-1360, (1978), Gillis, S. et al., J. Immunol., 120, 2027-2033, (1978)) or by stimulating human peripheral blood mononuclear lymphocytes with a mitogen (Gillis, S. et al., J. Immuno., 124, 1954-1962, (1980)). Gillis et al. reported the preparation of murine ILo2 from murine T cell lymphoma cell line (Gillis, S. et al. J. Immunol., 125, 2570-2578 (1980)) and preparation of human IL-2 from a human leukemia cell line (Gillis, S. et al., J. Exp. Med., 152, 1709-1719, (1980)).
Other methods of preparations, compositions and use thereof are illustrated by the following references.
U.S. Pat. No. 4,404,280 discloses a process for producing murine IL-2 from malignant neoplastic cells in vitro in a protein-containing medium. The process includes the utilization of IL-1 as a co-stimulant to induce IL-2 production.
U.S. Pat. No. 4,406,830 relates inter alia. to a process for producing a serum-free and mitogen-free IL-2 in vitro by adding glycoprotein to a serum-free and mitogen-free IL-1 preparation.
U.S. Pat. No. 4,738,927 discloses a method of producing IL-2 by isolating a gene which possesses IL-2 activity, connecting said gene with a vector DNA which is capable of replicating in a procaryotic or eucaryotic cell at a position down-stream of a promoter gene in the vector to obtain a recombinant DNA, with which the cell is transformed to produce IL-2.
U.S. Pat. No. 4,752,573 relates to the use of pterins to increase the activity of lymphokines and other cell growth factors, including IL-2.
U.S. Pat. No. 4,780,313 discloses a method for immunostimulating a warm-blooded animal by administering to said animal a substance having IL-2 activity, such as a recombinant non-glycosylated human IL-2, in combination with muramyldipeptide.
U.S. Pat. No. 4,789,658 relates to an immunoprophylactic and immunotherapeutic composition comprising grade E human IL-2 of human T-lymphocyte origin.
The utility of IL-2 to supplement immune responses and thus the need for IL-2 mediators to proliferate other effector cells, such as T-helper and suppressor cells, cytotoxic T-cells and natural killer cells (hereinafter NKC's) to promote cell-mediated immunity, is apparent from the above-described references.
It should also be noted that IL-1, or a biologically active compound that mimics IL-1 activity, plays a very important role as an immunostimulating agent by inducing IL-2 synthesis and subsequent IL-2 receptor expression.
We have now discovered a class of organic compounds which promote cell-mediated immunity based on their capability to elevate IL-2 and granulocyte macrophage colony stimulating factor (hereinafter GM-CSF) levels in vitro and thus proliferate effector cells, such as cytotoxic T-cells lines and other subpopulations of T-cells.